Help please

Please Help!

Write a Java application that prompts the user for pairs of inputs of a product number (1-5), and then an integer quantity of units sold. You must use a switch statement and a sentinel-controlled loop (i.e. a loop that stops execution when an out of range value, such as -1, is input). All 15 items below are for a single purchase. There are five sets of inputs as follows:

Product 1 1 unit (cost is $2.98 per unit)
Product 2 2 units (cost is $4.50 per unit)
Product 3 3 units (cost is $9.98 per unit)
Product 4 4 units (cost is $4.49 per unit)
Product 5 5 units (cost is $6.87 per unit)

Your application must calculate and display the total retail value of all products sold, after all 5 pairs of inputs are completed. You must also display the total after each new pair of input values is entered.

Here is what I have so far...It works ,however, I want to add in the final message window the total of the entire order.

Java Code:

// Sales.java
// Program calculates sales, based on an input of product
// number and quantity sold

import java.awt.*;
import java.text.NumberFormat;
import java.util.Locale;
import javax.swing.*;

public class Sales {

public static void main( String args[] )
{
float product1 = 0, product2 = 0, product3 = 0;
float product4 = 0, product5 = 0;

String inputString;

int productId = 1;
int totalCost = 0;

// ask user for product number until flag value entered
while (productId != 0) {

// determine the product chosen
inputString = JOptionPane.showInputDialog(
"Enter product number (1-5) 0 to Quit:" );
productId = Integer.parseInt( inputString );

if ( productId >= 1 && productId <= 5 ) {

// determine the number sold of the item
inputString = JOptionPane.showInputDialog(
"Enter quantity:" );
int quantity = Integer.parseInt( inputString );

// Calculate the total for the item by the
// price times the quantity sold
switch ( productId ) {

case 1:
product1 += quantity * 2.98;
break;

case 2:
product2 += quantity * 4.50;
break;

case 3:
product3 += quantity * 9.98;
break;

case 4:
product4 += quantity * 4.49;
break;

case 5:
product5 += quantity * 6.87;
break;

}

}

else if ( productId != 0 ) {
JOptionPane.showMessageDialog( null,
"Product number must be between 1 and 5 or -1 to Quit",
"Input Error", JOptionPane.INFORMATION_MESSAGE );
}
}


// create decimal format to format floating point numbers
// with two digits to the right of the decimal point
NumberFormat moneyFormat =
NumberFormat.getCurrencyInstance( Locale.US );

// create a summary message
String output = "Product 1: " + moneyFormat.format( product1 );
output += "\nProduct 2: "+ moneyFormat.format( product2 );
output += "\nProduct 3: " + moneyFormat.format( product3 );
output += "\nProduct 4: " + moneyFormat.format( product4 );
output += "\nProduct 5: " + moneyFormat.format( product5 ) + "\n";

JTextArea outputArea = new JTextArea( 6, 20 );
outputArea.setText( output );

// show results
JOptionPane.showMessageDialog( null, outputArea,
"Totals", JOptionPane.INFORMATION_MESSAGE );

System.exit( 0 );
}

} // end class Sales

I just can not figure out how to get it to display the subtotal after each pair of inputs.

Quote:

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Originally Posted by broodwich

I just can not figure out how to get it to display the subtotal after each pair of inputs.

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Your code just needed a bit of rearranging... by including an output screen in the loop "while (productId != 0)" you can show the user the results as they update it.
Also by declaring the "productId" variable type as "double" not "float", you can easily overwrite the previous value if it has changed (as your current code stands, the previous value is added to the new calculation with the "+=" operator.) I replaced them with "=" to overwrite, so if the user later enters 0 for the amount of a particular product, it's total will be $0 not previous calculation + $0).

Code:

---

public class Sales
{

    public static void main (String args[])
    {
        double product1 = 0, product2 = 0, product3 = 0,
            product4 = 0, product5 = 0;

        String inputString, output = "";

        int productId = 1;
        int totalCost = 0;

        // create decimal format to format floating point numbers
        // with two digits to the right of the decimal point
        NumberFormat moneyFormat =
            NumberFormat.getCurrencyInstance (Locale.US);



        // ask user for product number until flag value entered
        while (productId != 0)
        {

            // determine the product chosen
            inputString = JOptionPane.showInputDialog (
                    "Enter product number (1-5) 0 to Quit:");
            productId = Integer.parseInt (inputString);

            if (productId >= 1 && productId <= 5)
            {

                // determine the number sold of the item
                inputString = JOptionPane.showInputDialog (
                        "Enter quantity:");
                int quantity = Integer.parseInt (inputString);

                // Calculate the total for the item by the
                // price times the quantity sold
                switch (productId)
                {

                    case 1:
                        product1 = quantity * 2.98;
                        break;

                    case 2:
                        product2 = quantity * 4.50;
                        break;

                    case 3:
                        product3 = quantity * 9.98;
                        break;

                    case 4:
                        product4 = quantity * 4.49;
                        break;

                    case 5:
                        product5 = quantity * 6.87;
                        break;

                }

            }

            else if (productId != 0)
            {
                JOptionPane.showMessageDialog (null,
                        "Product number must be between 1 and 5 or -1 to Quit",
                        "Input Error", JOptionPane.INFORMATION_MESSAGE);
            }


            // create a summary message
            output = "Product 1: " + moneyFormat.format (product1);
            output += "\nProduct 2: " + moneyFormat.format (product2);
            output += "\nProduct 3: " + moneyFormat.format (product3);
            output += "\nProduct 4: " + moneyFormat.format (product4);
            output += "\nProduct 5: " + moneyFormat.format (product5) + "\n";
           
            if (productId != 0)
            {
                // show results
                JOptionPane.showMessageDialog (null, output,
                        "Current totals", JOptionPane.INFORMATION_MESSAGE);
            }
        }

        // show results
        JOptionPane.showMessageDialog (null, output,
                "Totals", JOptionPane.INFORMATION_MESSAGE);

        System.exit (0);
    }
} // end class Sales

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CHEERS!